Disposal of fine tailings

DETAILED DESCRIPTION I claim: 1.
A method of disposal of slurries of fine tailings material comprising laying a porous drainage level on a subsurface between a leading edge and a trailing edge, construction of a bund upon the porous drainage level and having a front face spaced inwardly from the leading edge of the porous drainage level and a rear face substantially forwardly of the porous drainage level trailing edge for leaving a substantial portion of the porous drainage level exposed, forming a further porous drainage level over the rear face of the bund to be covered by said fine tailings, depositing the slurries of fine tailings in layers behind said bund and at least in part over the porous drainage levels and providing still further porous drainage levels between the layers in the region adjacent said bund and in contact with the further porous drainage level for draining liquid from the layers.
2.
A method as claimed at claim 1 wherein said bund is formed substantially from dried fine tailings.
3.
A method as claimed at claim 1 wherein the entire area to be covered by said fine tailings is covered by the porous drainage level.
4.
A method as claimed in claim 3 wherein the bund is formed in stages where subsequent stages are supported by both the previously formed stage and drained consolidated tailings material adjacent said stage.
5.
A method as claimed at claim 4 wherein porous drainage levels comprise blankets of porous material.
6.
A method as claimed at claim 5 wherein said blanket comprises a gravel layer overlaid by a layer of sand.
7.
A method as claimed in claim 6 wherein the gravel layer is formed of clean gravel of approximately 2 to 30 mm sieve and fine sand of approximately 0.
06 to 2 mm sieve.
8.
A method as claimed at claim 7 wherein said gravel layer has a permeability of approximately 1.
times.
10.
sup.
-4 m/s and said sand layer has a permeability of approximately 1.
times.
10.
sup.
-5 m/s.
9.
A method as claimed in claim 8 wherein the gravel layer has a thickness of approximately 0